Massimi P, Pim D, Banks L
International Centre for Genetic Engineering and Biotechnology, Trieste, Italy.
J Gen Virol. 1997 Oct;78 ( Pt 10):2607-13. doi: 10.1099/0022-1317-78-10-2607.
We have previously shown that the human papillomavirus E7 proteins bind to the cellular TATA box binding protein (TBP). In this paper we show that the HPV-18 E6 and the HPV-16 E2 proteins will also bind TBP in vitro. This feature of virus proteins is conserved across many viral types and we were interested in determining whether these HPV proteins interacted with the same conserved region of the TBP molecule. A series of deletions was introduced into the TBP protein and its binding to these HPV proteins was measured. The previously well-characterized interaction between p53 and TBP was used for comparison. All four proteins were found to interact with the carboxy-terminal domain of the TBP protein, although the precise residues involved and the relative strengths of association differed between the different HPV proteins. Mutational analysis of HPV-16 E7 protein identified a stretch of four amino acids responsible for the binding to TBP. This mutant E7 protein possessed wild-type levels of transcriptional activity on the adenovirus E2 promoter but exhibited reduced transforming activity in cooperation with EJ-ras. These results demonstrate that the mechanisms of interaction between diverse viral proteins and TBP are similar and that, in the case of E7, this interaction may contribute to its transforming activity.
我们之前已经表明，人乳头瘤病毒E7蛋白可与细胞TATA盒结合蛋白（TBP）结合。在本文中，我们展示了HPV - 18 E6和HPV - 16 E2蛋白在体外也能与TBP结合。病毒蛋白的这一特性在许多病毒类型中都保守存在，我们感兴趣的是确定这些HPV蛋白是否与TBP分子的同一保守区域相互作用。我们对TBP蛋白进行了一系列缺失操作，并检测其与这些HPV蛋白的结合情况。以之前已充分表征的p53与TBP之间的相互作用作为对照。结果发现，所有这四种蛋白都能与TBP蛋白的羧基末端结构域相互作用，不过不同HPV蛋白之间，所涉及的精确氨基酸残基以及结合的相对强度有所不同。对HPV - 16 E7蛋白的突变分析确定了一段由四个氨基酸组成的序列负责与TBP结合。这种突变型E7蛋白在腺病毒E2启动子上具有野生型水平的转录活性，但与EJ - ras协同作用时转化活性降低。这些结果表明，不同病毒蛋白与TBP之间的相互作用机制相似，而且就E7而言，这种相互作用可能有助于其转化活性。
